U.S. patent application number 16/382636 was filed with the patent office on 2019-10-17 for power tool blade type detection and automatic speed adjustment.
The applicant listed for this patent is MILWAUKEE ELECTRIC TOOL CORPORATION. Invention is credited to John S. Dey, IV, Corey J. Dickert.
Application Number | 20190314946 16/382636 |
Document ID | / |
Family ID | 68161165 |
Filed Date | 2019-10-17 |
![](/patent/app/20190314946/US20190314946A1-20191017-D00000.png)
![](/patent/app/20190314946/US20190314946A1-20191017-D00001.png)
![](/patent/app/20190314946/US20190314946A1-20191017-D00002.png)
![](/patent/app/20190314946/US20190314946A1-20191017-D00003.png)
![](/patent/app/20190314946/US20190314946A1-20191017-D00004.png)
United States Patent
Application |
20190314946 |
Kind Code |
A1 |
Dey, IV; John S. ; et
al. |
October 17, 2019 |
POWER TOOL BLADE TYPE DETECTION AND AUTOMATIC SPEED ADJUSTMENT
Abstract
Systems and methods are provided for an electric tool (e.g., a
power tool) that includes an output driver for receiving an
accessory, and an accessory-type detector. A motor of the electric
tool is coupled to the output driver for driving the accessory. The
power tool also includes an operation trigger for activating the
motor and a motor controller. The motor controller includes an
electronic processor that is coupled to the accessory-type
detector, the motor, the operation trigger, and a memory. The
memory stores instructions that when executed by the electronic
processor cause the motor controller to detect a characteristic of
the accessory from output of the accessory-type detector. The motor
controller determines an operational characteristic for the
accessory based on the detected characteristic, and controls
operation of the motor to drive the accessory according to the
operational characteristic when the operation trigger is
activated.
Inventors: |
Dey, IV; John S.;
(Milwaukee, WI) ; Dickert; Corey J.; (Brookfield,
WI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MILWAUKEE ELECTRIC TOOL CORPORATION |
Brookfield |
WI |
US |
|
|
Family ID: |
68161165 |
Appl. No.: |
16/382636 |
Filed: |
April 12, 2019 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62656448 |
Apr 12, 2018 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23D 45/042 20130101;
B23D 59/001 20130101; B23D 45/044 20130101; B23Q 15/12 20130101;
B23G 1/225 20130101 |
International
Class: |
B23Q 15/12 20060101
B23Q015/12; B23D 59/00 20060101 B23D059/00; B23D 45/04 20060101
B23D045/04; B23G 1/22 20060101 B23G001/22 |
Claims
1. A method for controlling operation of a power tool, the method
comprising: receiving an accessory by an output driver of the power
tool, the output driver coupled to a motor of the power tool,
wherein the accessory is driven by the motor; detecting, by a motor
controller of the power tool, a characteristic of the accessory
using an accessory-type detector that is coupled to the motor
controller; determining, by the motor controller, an operational
characteristic for the accessory based on the characteristic of the
accessory detected by the motor controller; and automatically
controlling, by the motor controller, operation of the motor that
drives the accessory according to the operational characteristic
when an operation trigger of the power tool is activated.
2. The method of claim 1, wherein the power tool is a chop saw and
the accessory-type detector is mounted on a blade guard of the chop
saw.
3. The method of claim 1, wherein the accessory is a saw blade and
the accessory characteristic comprises a material of which the saw
blade is made.
4. The method of claim 1, wherein the operational characteristic
comprises a speed for rotating the motor that drives the output
driver and the accessory.
5. The method of claim 1, wherein the characteristic of the
accessory comprises a physical characteristic of the accessory or a
modification made to the accessory.
6. The method of claim 1 further comprising: disabling, by the
motor controller, activation of the motor when the accessory-type
detector detects that the accessory is not received by the output
driver.
7. The method of claim 1 further comprising: enabling activation of
the motor when the accessory-type detector detects that the
accessory is received by the output driver.
8. A power tool comprising: an output driver for receiving an
accessory; an accessory-type detector; a motor coupled to the
output driver for driving the accessory; an operation trigger for
activating the motor; and a motor controller comprising an
electronic processor coupled to the accessory-type detector, the
motor, the operation trigger, and a memory, wherein the memory
stores instructions that when executed by the electronic processor
configure the motor controller to: detect, from output of the
accessory-type detector, a characteristic of the accessory,
determine an operational characteristic for the accessory based on
the characteristic of the accessory detected by the motor
controller, and control operation of the motor to drive the
accessory according to the operational characteristic when the
operation trigger is activated.
9. The power tool of claim 8, wherein the power tool is a saw and
the accessory-type detector is mounted on a blade guard of the
saw.
10. The power tool of claim 8, wherein the power tool is a saw and
the accessory-type detector is mounted on a housing of the saw.
11. The power tool of claim 8, wherein the accessory is a saw blade
and the accessory characteristic comprises a material of which the
saw blade is made.
12. The power tool of claim 8, wherein the operational
characteristic comprises a speed for rotating the motor that drives
the output driver and the accessory.
13. The power tool of claim 8, wherein the characteristic of the
accessory comprises a physical characteristic of the accessory or a
modification made to the accessory.
14. The power tool of claim 8, wherein the motor controller is
further configured to: disable activation of the motor when the
accessory-type detector detects that the accessory is not received
by the output driver; and enable activation of the motor when the
accessory-type detector detects that the accessory is received by
the output driver.
15. The power tool of claim 8, further comprising: a material-type
detector, wherein the accessory is a saw blade, wherein the memory
stores further instructions that, when executed by the electronic
processor configure the motor controller to detect, from output of
the material-type detector, a characteristic of a workpiece for
cutting by the saw blade, and wherein determining the operational
characteristic for the accessory is further based on the detected
characteristic of the workpiece.
16. A chop saw comprising: an arbor configured to receive an
accessory in the form of a saw blade; a base configured to receive
a workpiece; a motor housing; a motor, supported by the motor
housing, that is coupled to the arbor for driving the arbor; a
hinge pivotably coupling the base to the motor housing; an
operation trigger for activating the motor; and an accessory-type
detector; a motor controller comprising an electronic processor
coupled to the accessory-type detector, the motor, the operation
trigger, and a memory, wherein the memory stores instructions that
when executed by the electronic processor configure the motor
controller to: detect, from output of the accessory-type detector,
a characteristic of the saw blade, determine an operational
characteristic for the saw blade based on the characteristic of the
saw blade detected by the motor controller; and control operation
of the motor to drive the saw blade according to the operational
characteristic when the operation trigger is activated.
17. The chop saw of claim 16, wherein the accessory-type detector
is mounted on a blade guard of the saw.
18. The chop saw of claim 16, the accessory characteristic
comprises at least one selected from the group of a material of
which the saw blade is made, a physical characteristic of the saw
blade, and a modification made to the saw blade.
19. The chop saw of claim 16, wherein the operational
characteristic comprises a speed for rotating the motor that drives
the arbor and the saw blade.
20. The chop saw of claim 16, further comprising: disabling, by the
motor controller, activation of the motor when the accessory-type
detector detects that the saw blade is not received by the output
driver; and enabling activation of the motor when the
accessory-type detector detects that the saw blade is received by
the output driver.
21. A pipe threader comprising: a die with teeth for cutting
threads on a pipe; a material-type detector; a motor coupled to the
die, the motor for driving rotation of the die; an operation
trigger for activating the motor; and a motor controller comprising
an electronic processor coupled to the material-type detector, the
motor, the operation trigger, and a memory, wherein the memory
stores instructions that when executed by the electronic processor
configure the motor controller to: detect, from output of the
material-type detector, a characteristic of a pipe received by the
die, determine an operational characteristic for threading the pipe
based on the detected characteristic of a pipe received by the die,
and control operation of the motor to drive rotation of the die
according to the operational characteristic when the operation
trigger is activated.
Description
RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application Ser. No. 62/656,448, filed on Apr. 12, 2018, which is
incorporated herein by reference in its entirety.
TECHNICAL FIELD
[0002] Embodiments described herein relate to power tools. More
specifically, embodiments described herein relate to automatic
control of power tools based on detection of power tool accessory
type or presence by an accessory-type detector.
SUMMARY
[0003] A power tool generally utilizes an accessory, such as, a
blade, a grinding disk, a drill bit, and the like for performing a
particular type of operation. Some power tools are configured to
interchange different accessories. Different power tool accessories
may have different characteristics, for example, they may be made
of different materials, have different dimensions, or they may be
designed to perform different tasks. The characteristics of a
particular accessory, or type of accessory, may affect the
performance of a power tool or may impose constraints on operation
of the power tool. For example, different accessory types may be
configured to work at different rotational speeds or applied
torque.
[0004] In some embodiments, a method for controlling operation of a
power tool includes receiving an accessory by an output driver of
the power tool. The output driver is coupled to a motor of the
power tool and the accessory is driven by the motor. A
characteristic of the accessory is detected by a motor controller
that is coupled to an accessory-type detector of the power tool.
The motor controller includes an electronic processor and a memory.
The motor controller determines an operational characteristic for
the accessory based on the detected characteristic of the
accessory. When an operation trigger of the power tool is
activated, the motor controller controls operation of the motor
that drives the accessory according to the operational
characteristic.
[0005] In some embodiments, a power tool includes an output driver
for receiving an accessory and an accessory-type detector. A motor
of the power tool is coupled to the output driver for driving the
accessory. The power tool also includes an operation trigger for
activating the motor and a motor controller. The motor controller
includes an electronic processor that is coupled to the
accessory-type detector, the motor, the operation trigger, and a
memory. The memory stores instructions that when executed by the
electronic processor, cause the motor controller to detect a
characteristic of the accessory from output of the accessory-type
detector. The motor controller determines an operational
characteristic for the accessory based on the detected
characteristic of the accessory, and controls operation of the
motor to drive the accessory according to the operational
characteristic when the operation trigger is activated.
[0006] In some embodiments, an electric tool includes an output
driver for receiving an accessory and an accessory-type detector. A
motor of the electric tool is coupled to the output driver for
driving the accessory. The electric tool also includes an operation
trigger for activating the motor and a motor controller. The motor
controller includes an electronic processor that is coupled to the
accessory-type detector, the motor, the operation trigger, and a
memory. The memory stores instructions that when executed by the
electronic processor, cause the motor controller to detect a
characteristic of the accessory from output of the accessory-type
detector. The motor controller determines an operational
characteristic for the accessory based on the detected
characteristic of the accessory, and controls operation of the
motor to drive the accessory according to the operational
characteristic when the operation trigger is activated.
[0007] In some embodiments, the accessory-type detector is coupled
to a housing of the electric tool or the power tool.
[0008] In some embodiments, the accessory is a saw and the
accessory characteristic comprises a material of which the saw is
made.
[0009] In some embodiments, the operational characteristic
comprises a speed for rotating the motor that drives the output
driver and the accessory.
[0010] In some embodiments, the characteristic of the accessory
comprises a physical characteristic of the accessory or a
modification made to the accessory.
[0011] In some embodiments, the motor controller disables
activation of the motor when the accessory-type detector detects
that an accessory is not received by the output driver.
[0012] In some embodiments, the motor controller may enable
activation of the motor when the accessory-type detector detects
that an accessory is received by the output driver.
[0013] Other aspects of the invention will become apparent by
consideration of the detailed description and accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 illustrates an example of an electric tool with an
accessory and an accessory-type detector.
[0015] FIG. 2 is a block diagram of the exemplary electric tool
with the accessory-type detector of FIG. 1.
[0016] FIG. 3 illustrates a method for controlling an electric tool
based on a type of accessory attached to the tool.
[0017] FIG. 4 illustrates an example of a pipe threader tool with a
pipe material-type detector.
DETAILED DESCRIPTION
[0018] One or more embodiments are described and illustrated in the
following description and accompanying drawings. These embodiments
are not limited to the specific details provided herein and may be
modified in various ways. Furthermore, other embodiments may exist
that are not described herein. Also, the functionality described
herein as being performed by one component may be performed by
multiple components in a distributed manner. Likewise,
functionality performed by multiple components may be consolidated
and performed by a single component. Similarly, a component
described as performing particular functionality may also perform
additional functionality not described herein. For example, a
device or structure that is "configured" in a certain way is
configured in at least that way, but may also be configured in ways
that are not listed. Furthermore, some embodiments described herein
may include one or more electronic processors configured to perform
the described functionality by executing instructions stored in
non-transitory, computer-readable medium. Similarly, embodiments
described herein may be implemented as non-transitory,
computer-readable medium storing instructions executable by one or
more electronic processors to perform the described functionality.
As used in the present application, "non-transitory
computer-readable medium" comprises all computer-readable media.
Accordingly, non-transitory computer-readable medium may include,
for example, a hard disk, a CD-ROM, an optical storage device, a
magnetic storage device, a ROM (Read Only Memory), a RAM (Random
Access Memory), register memory, a processor cache, or any
combination thereof.
[0019] In addition, the phraseology and terminology used herein is
for the purpose of description and should not be regarded as
limiting. For example, the use of "including," "containing,"
"comprising," "having," and variations thereof herein is meant to
encompass the items listed thereafter and equivalents thereof as
well as additional items. The terms "connected" and "coupled" are
used broadly and encompass both direct and indirect connecting and
coupling. Further, "connected" and "coupled" are not restricted to
physical or mechanical connections or couplings and can include
electrical connections or couplings, whether direct or indirect. In
addition, electronic communications and notifications may be
performed using wired connections, wireless connections, or a
combination thereof and may be transmitted directly or through one
or more intermediary devices over various types of networks,
communication channels, and connections. Moreover, relational terms
such as first and second, top and bottom, and the like may be used
herein solely to distinguish one entity or action from another
entity or action without necessarily requiring or implying any
actual such relationship or order between such entities or
actions.
[0020] Some electric tools are configured to receive multiple
different types of accessories, for example, saw blades (e.g.,
reciprocating or circular), grinding disks, drill bits, driver
bits, and variations thereof made of different materials, sizes,
and shapes. However, different accessories may work more
efficiently, more accurately, with less wear, or a combination
thereof, when utilized with different operational characteristics,
for example, different linear or rotational speeds, acceleration
patterns, or directions. In some embodiments described herein,
methods and systems provide a tool component that senses what type
of accessory is attached to the tool. The tool is configured to
automatically operate at the appropriate speed, acceleration, or
other operating characteristic based on the detected type of
attached accessory. For example, when a user turns the tool on, the
tool may operate at a speed or acceleration appropriate for the
attached type of accessory. In one example comprising a chop saw, a
blade type may be detected and a speed setting may be automatically
applied for driving the saw based on the blade type. When the blade
is replaced with a second type of blade (or a grinder, for example)
the second blade type is detected and the speed setting is
automatically changed to a second speed according to the second
type of blade.
[0021] FIG. 1 illustrates an example of an electric tool 100 with
an accessory and an accessory-type detector. In this example, the
electric tool 100 is a chop saw and may be referred to as the chop
saw 100. The electric tool 100 includes a tool housing 115, a blade
guard 120, a power interface 125, an accessory 135, a tool
activation trigger 140, and an accessory-type detector 145. The
accessory 135 in this example is a saw blade and may be referred to
as the blade 135. The housing 115 includes a motor housing 146, a
handle 147, a base 148, and a hinge 149 pivotably coupling the
motor housing 146 to the base 148. The electric tool 100 may also
be referred to as a power tool 100.
[0022] Although, the exemplary electric tool 100 is shown as a chop
saw, the electric tool 100 may be any electric tool (or power tool)
that drives an output driver. Such electric tools include, for
example, drills, circular saws, jig saws, band saws, table saws,
miter saws, reciprocating saws, angle grinders, straight grinders,
hammers, multi-tools, impact wrenches, rotary hammers,
drill-drivers, hammer drill-drivers, impact drivers, angle drills,
belt sanders, orbital sanders, planers, pipe cutters, grease guns,
vacuum cleaners, fluid flow control devices, outdoor power
equipment (such as blowers, chain saws, edgers, hedge trimmers,
lawn mowers, or trimmers), and the like. The vacuum cleaners can
include wet/dry vacuums, dust removal vacuums that may be
connectable to power tools (e.g., saws or sanders), stick vacuums,
hand vacuums, upright vacuums, carpet cleaners, hard surface
cleaners, canister vacuums, broom vacuums, and the like. The fluid
flow control devices can include motorized water pumps,
electronically controllable water flow valves, and the like. The
electric tool 100 may also include other types of appliances,
machines, or devices that receive and drive an accessory to perform
an operation.
[0023] In some embodiments, the housing 115 (in particular, the
motor housing 146), supports a motor (see FIG. 2) that drives the
accessory 135. For example, the motor may drive rotation of the
blade 135. The housing 115 may also support a motor controller and
other components that enable operation of the electric tool 100
(see FIG. 2). The blade guard 120 is mechanically coupled to the
housing 115 and is disposed around and/or beside the blade 135. The
blade guard 135 serves as a safety device to cover portions of the
blade 135. During operation, the trigger 140 is pulled to activate
the chop saw 100 and rotate the blade 135, and the handle is pulled
downward by the operator bringing the blade 135 toward the base 148
to cut a workpiece (not shown) that is received by and supported on
the base 148. The hinge 149 may be spring-biased such that the
motor housing 146 returns to an upright position as illustrated in
FIG. 1 when the operator releases the handle 147.
[0024] The accessory 135 includes a detectable characteristic. The
characteristic may be a physical characteristic of the accessory
135 or the accessory 135 may be modified with a characteristic that
identifies the accessory type. The accessory-type indicator, as a
characteristic of the accessory 135, may include an identifying
mark or an attached tag that may be sensed, read, or optically
captured by the accessory-type detector 145. Detectable physical
characteristics may include, for example, a type of material that
the accessory is made of, a texture, shape, or size of the
accessory 135 or a portion of the accessory 135. For example, a
metal accessory versus a non-metal accessory are two types of
materials that may be detected.
[0025] In some embodiments, the power interface 125 is configured
to receive a removable and rechargeable power tool battery pack
(not shown) that may be operable with a suite of two or more of
power tools, fluid flow control devices, test and measurement
devices, work site radios, and work lights. The power tool battery
pack includes a housing within which are one or more battery cells,
which may be lithium ion ("Li-ion") cells, Nickel-Cadium ("Ni-Cad")
cells, or cells of another chemical type. The cells, collectively,
may provide nominal voltages of different values, depending on the
pack. For example, the power tool battery pack may have a nominal
output voltage of 4V, 12V, 18V, 28V, 36V, 40V, a voltage between
levels, or other levels. In some embodiments, the power interface
125 is an alternating current (AC) power interface that is
configured to be connected to a standard AC outlet that is further
coupled to an AC power grid or AC generator. For instance, the AC
source may include an approximately 120 V, 60 Hz power signal or an
approximately 240 V, 50 Hz power signal.
[0026] The tool activation trigger 140 is coupled to the electronic
processor and supported by the housing 115 and may initiate
activation of the electric tool 100 when actuated or depressed by a
user.
[0027] The accessory-type detector 145 may be mounted on the blade
guard 120 (e.g., on the outside or on the inside of the blade guard
120), the tool housing 115, or on any other structure of the
electric tool 100 such that the accessory-type detector 145 can
detect which type of accessory 135 is attached to the power tool
100. For example, in some embodiments, the accessory-type detector
has a first sensing side and a second mounting side opposite the
first sensing side. The mounting side may be secured to the inside
of the blade guard 120 (e.g., via fasteners, adhesive, welding, and
the like), while the sensing side includes a sensor with a sensing
face directed toward a side face 135a of the blade 135. The
accessory-type detector 145 is configured to detect one or more
characteristics of the accessory 135. In some embodiments, the
accessory-type detector 145 includes an inductive sensor that
detects and provides an indication of whether the accessory 135 is
metal or non-metal. In some embodiments, the accessory-type
detector 145 includes an optical sensor that detects and provides
an indication of a characteristic such as the type, size, shape,
texture, or material of the accessory 135. Other suitable types of
sensors may be used as the accessory-type detector 145, for
example, radio frequency identification (RFID), sound, light,
tactile or heat sensors. In some embodiments, the accessory-type
detector 145 detects and provides an indication of whether or not
the accessory 135 is received in place, such as attached to the
electric tool 100. The controller may prevent activation of a tool
component when the tool activation trigger is pulled and the
accessory 135 is missing or placed incorrectly. Moreover, in some
embodiments, the accessory 135 may comprise an identifying mark or
a tag that may be sensed or read by the accessory-type detector
145, and may indicate which type of accessory 135 is attached to
the electric tool 100. The mark or tag may include, among other
things, one or more of an RF or RFID emitter, an optically
detectable feature such as a type of bar code, a color, a light
emitter, and an acoustically detectable feature or sound
emitter.
[0028] FIG. 2 is a block diagram of the exemplary electric tool 100
with the accessory-type detector 145 of FIG. 1. A system 200 of the
electric tool 100 includes, among other things, the power interface
125, the accessory-type detector 145, field effect transistors
(FETs) 205, a motor 210, an output driver 212, Hall sensors 215, a
motor controller 220, user input 225, and other components 230
(battery pack fuel gauge, work lights (LEDs), current/voltage
sensors, etc.). The motor controller 220 may also be referred to as
an electronic motor controller or a motor microcontroller and
includes, among other things, an electronic processor and a memory.
In some embodiments, the memory stores instructions that are
executed by the electronic processor to implement the functionality
of the motor controller 220 described herein.
[0029] The output driver 212 is configured to receive an electric
tool accessory 135, for example, a blade or drill. The output
driver 212 is, for example, an arbor for receiving a saw blade or a
chuck for receiving a drill bit. The accessory-type detector 145
detects characteristics of the accessory 135 and communicates data
indicating the accessory characteristics to the motor controller
220. The Hall sensors 215 provide motor information feedback, such
as motor rotational position information, which can be used by the
motor controller 220 to determine motor position, velocity, and/or
acceleration. The motor controller 220 receives user controls from
user input 225, such as by depressing the trigger 140 or shifting a
forward/reverse selector of the electric tool 100. In response to
the accessory characteristic, the motor information feedback,
and/or user controls, the motor controller 220 transmits control
signals to accurately control the FETs 205 to drive the motor 210.
By selectively enabling and disabling the FETs 205, power from the
power interface 125 is selectively applied to stator windings of
the motor 210 to cause rotation of a rotor of the motor 210. The
rotating rotor of the motor 210 drives the output driver 212 and
the accessory 135 at an appropriate operational characteristic,
such as a specified speed, acceleration, and/or direction,
according to the accessory characteristic. Although not shown, the
motor controller 220 and other components of the electric tool 100
are electrically coupled to and receive power from the power
interface 125. The FETs 205 may also be referred to as power
switching elements. The FETs 205, motor 210, Hall sensors 215,
motor controller 220, and output driver 212 may be referred to as
electromechanical components 235 of the electric tool 100.
[0030] As noted above, the accessory-type detector 145 detects one
or more accessory characteristics of the accessory 135 on the
output driver 212 and outputs data to the motor controller 220
indicative of the detected one or more accessory characteristics.
Further, in some embodiments, the accessory-type detector 145 is
configured to output an indication to the motor controller 220 of
whether an accessory is coupled to the output driver 212. In some
embodiments, the accessory-type detector 145 is one or more of an
inductive sensor, an optical sensor, a radio frequency
identification (RFID) sensor, sound sensor (microphone), a light
sensor, a tactile sensor, and a heat sensor.
[0031] Although described with respect to the example of the chop
saw 100 of FIG. 1, the block diagram 200 generally applies to other
embodiments of the electric tool 100. For example, the output
driver 212 in the case of a power drill-driver is a chuck; the
output driver 212 in the case of a vacuum is an impeller providing
suction force; and the output driver 212 in the case of a water
pump is a pumping mechanism. Further, in some embodiments of the
electric tool 100, a brushed motor is provided as the motor 210 to
drive the output driver 212.
[0032] FIG. 3 illustrates a method 300 for controlling an electric
tool based on a type of accessory attached to the tool. In some
embodiments, the method 300 is implemented with one of the
embodiments of the electric tool 100 of FIG. 1 and, accordingly,
the method 300 will be described with respect to the system 100.
However, in some embodiments, the method 300 is implemented with
other systems or other types of electric tools as described
above.
[0033] In block 305, the power tool 100 receives the accessory 135
at the output driver 212. As part of receiving the accessory 135,
in some embodiments, the output driver 212 is tightened, clamped,
or otherwise manipulated (e.g., by a user) to retain the accessory
135. For example, in some embodiments, the power tool 100 is a chop
saw that receives at an arbor a blade or grinder from a plurality
of different types of blades and grinders.
[0034] In block 310, an accessory-type detector 145, coupled to or
integrated within the electric tool 100, detects a characteristic
of the accessory 135. As noted above, in some embodiments, the
accessory-type detector 145 is connected to the electric tool 100
such that the accessory-type detector 145 detects the accessory
characteristic of the accessory 135. For example, the
accessory-type detector 145 may be mounted on the housing 115 or
the blade guard 120. The motor controller 220 receives data from
the accessory-type detector 145 that indicates the accessory
characteristic. For example, in some embodiments, the accessory
characteristic is at least one selected from the group of a
material type (e.g., metal versus non-metal), a blade type (e.g.,
chop saw blade versus grinder), a texture, shape, or size of the
accessory or a portion of the accessory, and an identifying mark
(e.g., that identifies one or more of the type of accessory, model
number, material type, blade type, texture type, shape, or size).
For example, the accessory-type detector 145 may be an inductive
sensor that outputs a digital signal indicating the presence or
absence of metal (e.g., digital logic signal of "0" indicates
metal, digital logic signal of "1" indicates non-metal). In another
embodiment, the accessory-type detector 145 is a bar code reader
that outputs a first value when no bar code is read or an invalid
bar code is read, and outputs another value indicative of a read
bar code value when a bar code is read. In another embodiment, the
accessory-type detector 145 is an optical sensor, Hall sensor,
inductive sensor, capacitive sensor, or the like, that outputs an
analog signal (e.g., between 0-3.3 volts or 0-5 volts) indicative
of the sensed characteristic. For example, the range of potential
analog signal values corresponds to the levels of the
characteristic that can be sensed by the sensor. For example, when
the accessory-type detector 145 is a Hall sensor, the sensor
outputs 0 volts when no or very low magnetic field is sensed, and
outputs 2.5 volts when a medium strength magnetic field (e.g., from
a magnet on the accessory 135) is sensed, and outputs 5 volts when
a strong magnetic field is sensed. Various other sensor types and
configurations are contemplated in different embodiments.
[0035] In block 315, the motor controller determines an operational
characteristic for the accessory 135 based on the accessory
characteristic. The memory of the motor controller 220 may
associate various accessory characteristics to corresponding
accessory operational characteristics for controlling the motor 210
and the accessory 135.
[0036] For example, in some embodiments, the memory of the motor
controller 220 includes a data table mapping accessory
characteristics to operational characteristics, where the accessory
characteristics serve as an index into the table and the
operational characteristics are corresponding outputs of the table.
For example, in some embodiments, the memory maps an abrasive blade
type (an accessory characteristic of some chop saw blades) to a
first motor speed (an example operational characteristic), and a
metal blade (an accessory characteristic of some other chop saw
blades) to a second motor speed (another example operational
characteristic), where the first motor speed is faster than the
second motor speed. However, the disclosure is not limited to this
or other specific mappings between accessory characteristics to
corresponding operational characteristics. The data table may be
generated through testing and stored in the memory at the time of
manufacture and/or may be updated. Additionally, the data table may
be particular to the type of electronic tool 100. In other words,
as an example, the data table for a chop saw may be different than
the data table for a drill-driver.
[0037] In block 320, when the power tool trigger 140 is actuated by
a user, the motor controller controls operation of the motor 210 to
drive the output driver 220 and the accessory 135 according to the
operational characteristic determined based on the accessory
characteristic. For example, in some embodiments, the operational
characteristic sets a pulse width modulated (PWM) duty ratio for
driving the FETs 205, which thereby sets the speed of the motor
210. For example, when cycling power to the FETs 205 to drive the
motor, the driving signal selectively provided by the motor
controller 220 to each FET 205 is provided with the determined PWM
duty ratio. In other embodiments, the operational characteristic is
a current driving value, a current threshold, an input into a
proportional-integral-derivative (PID) controller setting a target
motor speed or other operational characteristics of the electronic
tool 100.
[0038] In some embodiments, in block 310, in addition to or instead
of the accessory-type detector 145 detecting a characteristic of
the accessory 135, the accessory-type detector 145 detects, and
provides an indication to the motor controller 220, of whether an
accessory is coupled to or properly coupled to the output driver
212. In response to receiving an indication from the accessory-type
detector 145 that an accessory is not coupled or not properly
coupled to the output driver 212, the motor controller 220 disables
activation of the motor based on the accessory-type detector 145
detecting that the accessory is not received by the output driver
212. For example, the motor controller 220 may continue to loop on
block 310 until an accessory is detected as coupled or properly
coupled to the output driver 212, rather than proceeding to block
315. However, in response to receiving an indication from the
accessory-type detector 145 that an accessory is coupled or
properly coupled to the output driver 212, the motor controller
enables activation of the motor based on the accessory-type
detector detecting that an accessory is received by the output
driver. For example, the motor controller 220 may proceed to block
315 upon detecting that an accessory is coupled or properly coupled
to the output driver 212. In one embodiment, the motor controller
220 determines that an accessory is coupled when the accessory-type
detector 145 outputs valid data. For example, when the
accessory-type detector 145 is a Hall sensor and the accessories
are expected to have a magnet to be sensed by the Hall sensor, an
indication of 0 volts (or less than some threshold value) from the
Hall sensor may indicate the absence of the accessory 135, while an
indication of 5 volts (or above some threshold value) because the
magnetic field of the magnet of the accessory 135 impinges the
sensor indicates the presence of the accessory 135.
[0039] As noted above, although the exemplary electric tool 100 is
shown as a chop saw, the electric tool 100 may be any electric tool
(or power tool) that drives an output driver. FIG. 4 illustrates an
example of a pipe threader electric tool that has a pipe
material-type detector. Referring to FIG. 4, a pipe threader 410
has a housing 414 including a gearcase 416, a drive assembly 418
including a motor and a transmission (not shown), and a die holder
430 for selectively receiving a die 434 with teeth for cutting
threads on a pipe (not shown) and defining a rotational axis 432.
The motor is powered by a battery 438 that is selectively coupled
to the housing 414. The housing 414 further includes an operating
handle 442 and a support handle 446. The pipe threader 410 includes
a trigger 450 on the operating handle 442 for activating the motor,
and a speed shift knob 454 allowing an operator to switch the die
holder 430 (and thus the die 434) between a high rotational speed
and a low rotational speed. The pipe threader 410 has a
material-type detector 412 that is mounted on the housing 414. The
pipe threader 410 also includes a motor controller, such as the
motor controller 220, that is also communicatively coupled to the
material-type detector 412 and the pipe threader motor (the motor
210), as illustrated in FIG. 2. In some embodiments of the pipe
threader, the motor controller 220 is configured to read sensor
data from the material-type detector 412 and control operational
characteristics of the pipe threader 410 such as speed, torque,
current draw, or other motor or tool performance
characteristic.
[0040] The material-type detector 412 may be mounted on the housing
414 or another structure of the pipe threader 410 such that the
material-type detector 412 is able to detect the type of material
of the pipe. In some embodiments, the material-type detector 412
has a first sensing side and a second mounting side opposite the
first sensing side. The mounting side may be secured to the housing
414 (e.g., via fasteners, adhesive, welding, and the like), while
the sensing side includes a sensor with a sensing face directed
toward a surface of a pipe that is received by the pipe threader
410. The material-type detector 412 is configured to detect one or
more characteristics of the pipe. In some embodiments, the
material-type detector 412 includes an inductive sensor that
detects and provides an indication of whether the pipe is metal or
non-metal. In some embodiments, the material-type detector 412
includes an optical sensor that detects and provides an indication
of a characteristic such as the type, size, shape, texture, or
material of the received pipe. Other suitable types of sensors may
be used as the material-type detector 412, for example, radio
frequency identification (RFID), sound, light, tactile or heat
sensors. Moreover, in some embodiments, the received pipe may
comprise an identifying mark or a tag that may be sensed or read by
the material-type detector 412, and may indicate which type of pipe
is received by the pipe threader 410. The mark or tag may include,
among other things, one or more of an RF or RFID emitter, an
optically detectable feature such as a type of bar code, a color, a
light emitter, and an acoustically detectable feature or sound
emitter.
[0041] The material-type detector 412 is configured to sense the
type of material from which the pipe is made (e.g., when the pipe
is received by the pipe threader for threading). Based on the type
of material sensed by the material-type detector 412, the motor
controller 220 is configured to vary operational characteristics
such as speed, torque, pressure, or other motor or tool performance
characteristic to improve the threading of the pipe being threaded.
For example, an operator may arrange the die 434 on a pipe to be
threaded and the material-type detector 412 may determine the type
of material of the pipe. The operator may press against a
non-rotating portion of the die 434 in the direction of the
rotational axis 432. The operator then presses trigger 450 to
activate the motor. As a result, the transmission transmits torque
from the motor to the die holder 430 such that the die holder 430
rotates while holding the die 434, causing the die 434 to rotate
and move along the pipe to cut threads on the pipe. Based on the
type of material sensed by the material-type detector 412, the
motor controller 220 is configured to vary operational
characteristics of the pipe threader 410 such as the speed, torque,
pressure, and/or other motor or tool performance characteristic to
improve the threading of the pipe. For example, the motor
controller 220 may increase the speed or torque of the motor 126 by
increasing the duty cycle of a PWM signal that forms the control
signals provided to the FETs 205, resulting in increased current
flowing to the stator coils of the motor 210. Similarly, the motor
controller 220 may decrease the speed or torque of the motor 126 by
reducing the duty cycle. The particular operational characteristic
for a particular detected material may specified in a lookup table
stored in the memory of the motor controller 220. For example, the
motor controller 220 may apply the identified material type to the
lookup table as an input/index, and the output of the lookup table
indicates the operational characteristic.
[0042] In another embodiment, the electronic tool 100 may be a saw
(e.g., the chop saw as shown in FIG. 1, reciprocating saw, or
circular saw) that includes a material-type detector 412. The
material-type detector 412 may be also be mounted on a housing,
blade guard, or any other structure of the saw such that the
material-type detector 412 is able to detect the type of material
of the work piece. For example, in FIG. 1, the material-type
detector 412 is shown integrated into the base of the chop saw. The
material-type detector 412 is configured to sense the type of
material that is being cut (e.g., metal, wood, a density of wood,
etc.). For example, the material-type detector 412 may be a
ferromagnetic sensor or a density sensor, etc. Using similar
techniques as described above, based on the type of material sensed
by the material-type sensor 412, the motor controller 220 is
configured to vary an operational characteristic such as speed,
torque, current draw, or other motor or tool performance
characteristic to improve cutting performance of the work piece
based on the type of material being cut. In some embodiments, with
reference FIG. 3, the motor controller 220 determines the
operational characteristic in block 315 based on both the
identified accessory type of the accessory 135 (detected by the
accessory type detector 145) and the identified material type of
the workpiece (detected by the material-type detector 415). For
example, a lookup table stored in the memory of the motor
controller 220 may map accessory types and workpiece material types
to an operational characteristic.
[0043] Thus, the disclosure provides, among other things, automatic
control of power tools based on detection of power tool accessory
type or accessory presence by an accessory-type detector. Various
features and advantages of the disclosure are set forth in the
following claims.
* * * * *